Re: [RFCv2] mm: page allocation for less fragmentation

Gioh Kim
2015-03-25T21:16:24Z

2015-03-25 오후 7:56에 Mel Gorman 이(가) 쓴 글:
> On Wed, Mar 25, 2015 at 11:39:15AM +0900, Gioh Kim wrote:
>> My driver allocates more than 40MB pages via alloc_page() at a time and
>> maps them at virtual address. Totally it uses 300~400MB pages.
>>
>> If I run a heavy load test for a few days in 1GB memory system, I cannot allocate even order=3 pages
>> because-of the external fragmentation.
>>
>> I thought I needed a anti-fragmentation solution for my driver.
>> But there is no allocation function that considers fragmentation.
>> The compaction is not helpful because it is only for movable pages, not unmovable pages.
>>
>> This patch proposes a allocation function allocates only pages in the same pageblock.
>>
>
> Is this not what CMA is for? Or creating a MOVABLE zone?

It's not related to CMA and MOVABLE zone.
It's for compaction and anti-fragmentation for any zone.

>